1. Field of the Invention
The present invention relates to a method of and an apparatus for weaving a three-dimensional article from a plurality of fibers with weaving means having a plurality of carrier members.
2. Description of the Background Art
For the purpose of reinforcing plastic, metal and the like, a method has been employed in which a plurality of prepregs, which are formed into plane-forms by reinforcing fibers such as carbon fiber, glass fiber, metallic fiber and the like, are laminated to be a multilayer, and then the laminated prepregs are buried into a material to be reinforced, for example a plastic material.
However such a conventional reinforcing method has the following disadvantages: Since fibers of the reinforced article are not arranged in three-dimensional direction, it is comparatively difficult to use a large quantity of reinforcing fibers, and the strength of the reinforced article can not be sufficiently improved because of low shear strength between fiber-layers arranged in the plane-forms.
To solve the above disadvantages, a method of reinforcing plastic, metal and the like, has been proposed by using what is called "a three-dimensional article" such as a braid or a braided article made by improving the braid.
A method of weaving the three-dimensional article is disclosed in the specification of U.S. Pat. No. 4,312,261. The weaving method is of a kind called the torsion lace method.
In the weaving method, a plurality of carrier members loaded with bobbins are arranged in the form of a matrix within a limmited plane. Each carrier member has magnets on the side surfaces thereof, and a plurality of electromagnetic solenoids are provided at the peripheral part of the limmited plane for the purpose of driving the carrier members. The carrier members are moved by the electromagnetic solenoids per line of carrier members along a row direction or a column direction in order to relatively change the position of the bobbins, so that fibers are intertwined with each other to form a three-dimensional article.
In the above weaving method, when a three-dimensional article having a special sectional form such as L-type, I-type, C-type and the like is woven, the carrier members are arranged in the form corresponding to the special sectional form, while a plurality of electromagnetic solenoids making up a carrier member driver are arranged along the periphery of the carrier members, and then the carrier members are alternately moved along the row and column directions per line of carrier members to weave a three-dimensional article. In such a weaving method, however, whenever the sectional form of the three-dimensional article changes, it is required to change the layout of the carrier member drivers. Further, when a three-dimensional article having a complicated sectional form such as a hollow-type and the like is woven, it is difficult to layout the carrier member drivers.
We proposed a weaving apparatus capable of industrially producing in high-speed a large-sized three-dimensional article in Japanese Patent Laying-Open Gazette No. 50553/1988. According to the weaving apparatus, since a plurality carrier members are individually driven by drivers such as linear motors and the like, it is possible to weave many kinds of three-dimensional articles having different sectional forms by using only one apparatus, thus the above problem can be solved. In such a weaving apparatus, however, it is required to provide expensive drivers such as linear motors and the like per individual carrier members, so that a facility cost and a running cost increase extremely.
On the other hand, the other weaving apparatus employing the torsion lace method is disclosed in U.S. Pat. No. 3,426,804.
In the weaving apparatus, a plurality of carrier members passing through fibers are arranged in the form of a matrix, and carrier member drivers having cam mechanisms are provided at the peripheral part of the carrier members for the purpose of driving the carrier members. The carrier members are moved by the carrier member drivers per line of carrier members along a row direction or a column direction in order to change the relative position of the carrier members, so that the fibers are intertwined with each other to form a three-dimensional article.
In the above weaving apparatus, however, each line of carrier members is moved along the surfaces of an adjacent line of carrier members, and therefore, when a certain line of carrier members are arranged so unevenly that the surfaces thereof may be irregular, it is difficult to cause the adjacent line of carrier members to move because the movement thereof is limited by the irregular surfaces.
In particular, the carrier members arranged on the same lines change whenever the carrier members alternately move in the rectangular two directions, and therefore it is not easy to cause each line of carrier members to line up. Accordingly, for the purpose of preventing the surfaces of each line of carrier members from being irregular, a high manufacturing accuracy of the carrier members is required. It is also required to use such material for the carrier members so that deformation with the passage of time and abrasion caused by the repeated movement of the carrier members may be decreased. As a result, the manufacturing cost of the carrier members significantly increases. In particular, the above problem often appears when the carrier members are moved at high speed.
Further, the other weaving apparatus employing the torsion lace method is disclosed in British patent No. 1,356,524.
In the weaving apparatus, track members having a plurality of guide grooves along the longitudinal direction thereof are provided in parallel along the width direction thereof, and carrier members supporting one end of wires are contained into the guide grooves respectively. The movement of carrier members in the row direction is performed by moving the track members in the longitudinal direction thereof, while the movement of carrier members in the column direction is performed by sliding the carrier members to the adjacent track members along the guide grooves.
According to the weaving apparatus, smooth movement of the carrier members can be accomplished in the column direction owing to a guide function of the guide grooves. However, the smooth movement of carrier members in the row direction is prevented when the number of the carrier members increases. It is difficult to manufacture such a carrier member because the width thereof is entirely equal to the width of the track member. In such a case where the number of the carrier members arranged in the column direction increases, when the carrier members are moved in the column direction, some of carrier members are moved so that they are positioned between the track members adjoining each other. Thus, that these carrier members prevent the next movement of carrier members in the row direction.
A weaving method is disclosed in U.S. Pat. No. 4,621,560 which allows the carrier members to be moved smoothly in both row and column directions, while using track members which have the same constructions as that of the above track members in British patent No. 1,356,524.
According to the above weaving method, although the movement of carrier members in the column direction is performed by causing all of the carrier members to move along the guide grooves simultaneously, the movement of carrier members in the row direction is sequentially performed. The area having all of the carrier members moving in the row direction is segmented into a plurality of blocks. Namely, first the n-th row of track member is moved in the longitudinal direction (i.e. the row direction) thereof, so that the carrier members contained in the first to n-th rows of track members are lined up in row direction respectively, and then the first to n-th rows of track members are moved along the longitudinal direction thereof to move the first to n-th rows of carrier members in the row direction respectively. Next, the 2n-th row of carrier members is moved along the longitudinal direction (i.e. the row direction) thereof, so that the carrier members contained in the (n+1)-th to 2n-th rows of track members are lined up along row direction respectively, and then the (n+1)-th to 2n-th rows of track members are moved along the longitudinal direction thereof to move the (n+1)-th to 2n-th rows of carrier members along row direction respectively. Similarly, the (2n+1)-th to 3n-th rows of carrier members, the (3n+1)-th to 4n-th rows of carrier members, . . . are sequentially moved along the row direction, thus the movement in the row direction of all rows of carrier members is completed. Therefore, the weaving method makes necessary a great amount of weaving since the movement of carrier members in the row direction is sequentially performed by each segmented block.